A decay study of windthrown indigenous trees

Abstract

The fungal communities within six stems each of matai (Prumnopitys taxifolia (D. Don) Laubenf.) and rimu (Dacrydium cupressinum Lamb.) were studied nearly four years after windthrow in a dense podocarp forest in the central North Island. There was a significant decrease in yield of isolates of all fungi as well as basidiomycetes in particular with increasing radial depth beneath the cambium (P < 0.01). The decrease was greater for matai than for rimu (P < 0.01). Fewer isolates of either group were obtained from heartwood (0-6% of attempts) than from sapwood and rimu transition wood (13-43%; P < 0.01). Among the basidiomycetes 85% of isolates belonged to eight species or generic groups six of which varied significantly in occurrence between trees (P < 0.05). The condition of the root systems in uprooted trees of four species (matai; rimu; miro Prumnopitys ferruginea (D. Don) Laubenf and tawa Beilschmiedia tawa (A. Cunn.) Benth and et Hook f. ex Kirk) was evaluated in the same forest. On matai and rimu trees a greater mean percentage of emergent roots was decayed at the centre of the exposed surface of the root-soil plate than around the margin (P < 0.05). Matai and rimu roots were significantly more decayed in this exposed central zone than were those of miro and tawa (P < 0.05). Rigidoporus catervatus (Berkeley) Corner was shown to be responsible for a white pocket rot in the heartwood and roots of living trees, and sapwood of fallen logs. © 1989 Taylor & Francis Group, LLC.